Hi Oleg,

I was able to write a simple Test Server that reproduces this issue. I
changed the NHttpFileServer example to come up with an example. If you send
a POST request with a dummy payload and a "Connection:close" header to this
server in 8443 port, you can see that the connection will not be closed
(JDK11 & JDK8_261) and the CPU will be spinning continuously processing
Write Events. If you start the same server in JDK8 (JDK8_251), the session
will close normally.

Please go through the example and provide your suggestions.

Regards,
Arunan

On Tue, Oct 13, 2020 at 11:07 AM Oleg Kalnichevski <[email protected]> wrote:

> On Tue, 2020-10-13 at 08:42 +0530, Arunan Sugunakumar wrote:
> > Hi Oleg,
> >
> > I upgraded to 4.4.13. Still the issue is there.
> >
>
> Provide a reproducer.
>
> Oleg
>
> > Regards,
> > Arunan
> >
> > On Mon, Oct 12, 2020, 20:56 Oleg Kalnichevski <[email protected]>
> > wrote:
> >
> > > On Sun, 2020-10-11 at 22:16 +0530, Arunan Sugunakumar wrote:
> > > > Hi,
> > > >
> > > > We have used httpcore-NIO to implement a non-blocking server and
> > > > with
> > > > a recent JAVA upgrade, we are finding a high CPU usage in our
> > > > servers. While we debugged, we found out that when we close the
> > > > HTTPS
> > > > connection on the server-side, the WRITE event is getting
> > > > fired continuously and the connection close is unsuccessful.
> > > >
> > > > To explain the code, we have extended DefaultNHttpConnectionBase
> > > > with
> > > > our own ServerConnection, and inside close() we simply just call
> > > > the
> > > > close() method of the NHttpConnectionBase[1]. If we look at the
> > > > code
> > > > below, the close method sets the status as CLOSING and after that
> > > > either sets the WRITE event in the session or tries to close the
> > > > session (SSLIOSession in our case).
> > > >
> > > > @Override
> > > > public void close() throws IOException {
> > > >     if (this.status != ACTIVE) {
> > > >         return;
> > > >     }
> > > >     this.status = CLOSING;
> > > >     if (this.outbuf.hasData()) {
> > > >         this.session.setEvent(EventMask.WRITE);
> > > >     } else {
> > > >         this.session.close();
> > > >         this.status = CLOSED;
> > > >     }
> > > > }
> > > >
> > > > Inside SSLIOSession close(), the updateEventMask() [2] is called.
> > > > @Override
> > > > public synchronized void close() {
> > > >     if (this.status >= CLOSING) {
> > > >         return;
> > > >     }
> > > >     this.status = CLOSING;
> > > >     if (this.session.getSocketTimeout() == 0) {
> > > >         this.session.setSocketTimeout(1000);
> > > >     }
> > > >     try {
> > > >         updateEventMask();
> > > >     } catch (final CancelledKeyException ex) {
> > > >         shutdown();
> > > >     }
> > > > }
> > > >
> > > > Inside updateEventMask() method, we get the HandshakeStatus from
> > > > the
> > > > JAVA SSLEngine, and set a new Mask based on the status.
> > > > switch (this.sslEngine.getHandshakeStatus()) {
> > > > case NEED_WRAP:
> > > >     newMask = EventMask.READ_WRITE;
> > > >     break;
> > > > case NEED_UNWRAP:
> > > >     newMask = EventMask.READ;
> > > >     break;
> > > > case NOT_HANDSHAKING:
> > > >     newMask = this.appEventMask;
> > > >     break;
> > > > case NEED_TASK:
> > > >     break;
> > > > case FINISHED:
> > > >     break;
> > > > }
> > > > Before JDK upgrade, when outbound is closed, we used to get the
> > > > status as NEED_UNWRAP which sets the newMask as READ mask which
> > > > closes the connection in our server perfectly.
> > > > But with a recent JDK commit[3], the new status is returned as
> > > > NOT_HANDSHAKING.
> > > > Since mask is not set to READ because of the NOT_HANDSHAKING
> > > > status,
> > > > WRITE event is continuously getting fired which makes the Server
> > > > connection close unsuccessful.
> > > > When the close is called multiple times for multiple connections,
> > > > we
> > > > could observe that CPU usage increased continuosly and reached
> > > > 100
> > > > percent and stays there continuously.
> > > > When I look at the stack trace, the execution flow was completely
> > > > inside the httpcore-nio component, which made our attempt to
> > > > clear
> > > > the Event from the server implementation, unsuccessful.
> > > >
> > > >
> > > > Earlier we were using Httpcore-NIO version 4.3.3. With this
> > > > issue, we
> > > > tried upgrading to 4.4.13. But still the issue exists.
> > >
> > > I have seen no evidence supporting that. Please upgrade to 4.4.13.
> > >
> > > Oleg
> > >
> > >
> > >
> > > -----------------------------------------------------------------
> > > ----
> > > To unsubscribe, e-mail: [email protected]
> > > For additional commands, e-mail: [email protected]
> > >
> > >
>
>
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-- 
*Sugunakumar Arunan*
Software Engineer | WSO2

Email : [email protected]
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